The document FR-A-2 708 237 describes an example of such a hinge mechanism, in which:                the first set of gear teeth is integral with the first frame,        the first toothed element is an eccentric circular set of gear teeth with respect to the first set of gear teeth, oriented radially outwards and integral with the second frame,        and the second toothed element is a set of eccentric circular gear teeth with respect to the additional set of gear teeth, oriented radially inwards and integral with the second frame.        
This hinge mechanism gives complete satisfaction. In particular, the additional set of gear teeth and the second toothed element of this hinge mechanism make it possible to increase the mechanical strength of the hinge mechanism, in particular in the case of a road accident when this mechanism is used in a vehicle seat. However, this principle can be used only with a hypocycloidal gear adjustment device.